Reviews on proteins, about 4000

1. The following description of proteins is incorrect (d).

a.It is the material basis of all life.

b.It is composed of elements such as carbon, hydrogen, oxygen, nitrogen, sulfur, etc.

c.Approximately 16% of body weight

d.Proteins in the body remain constant and do not renew.

Second, the function of proteins.

1.The building of the immune system is a grinding code.

Protein is the material basis for the body's immune defense function, and is closely related to the histogenesis and organ development of the immune system. The production of various immune cells and the synthesis of antibodies require proteins and amino acids as raw materials or participate in their processes. If the protein intake is insufficient and the immune system is not strong enough, foreign viruses and bacteria can easily invade the body and cause diseases.

2.Maintain normal metabolism.

The cells and tissues of the human body are metabolically renewed. For example, the human cell will be renewed every 28 days, starting from the lowest basal layer and continuing to grow upward, constantly accumulating to produce keratin. It takes 14 days for the stratum corneum to grow, and 14 days from the time it becomes a stratum corneum to fall off.

If there is a lack of protein, the cell tissue cannot be differentiated and metabolized in time, and it will become dull yellow and dull.

3.Provides special amino acids.

There are more than 20 kinds of amino acids related to the human body, of which 8 kinds cannot be synthesized by the human body, and must be ingested from foods containing protein, which are called essential amino acids.

The following description of protein is incorrect (d).

a.It is the material basis of all life.

b.It is composed of elements such as carbon, hydrogen, oxygen, nitrogen, sulfur, etc.

c.Approximately 16% of body weight

d.The proteins in the body remain constant and do not renew wax mine.

The five functions of proteins include:

It is composed of repairing human tissues, mediating and maintaining the physiological functions of the body, participating in energy supply, maintaining the osmotic balance of body fluids, and maintaining the acid-base balance of the blood.

1) Construct the tissue and repair the tissue. Protein is the main material that makes up tissue cells. The human brain, nerves, muscles, internal organs, blood, and even nails and hair are all made of protein.

Protein is the main component of the development and growth of the body, the renewal of aging tissues after growth, and the regeneration and repair of tissues after injury.

2) Components that make up enzymes and certain hormones.

3) Enhance the body's immunity and constitute antibodies. The strength of the body's immunity depends on the amount of antibodies against diseases.

4) Regulate osmotic pressure. In normal people, there is a constant exchange of water between plasma and tissue fluid, but it remains balanced. Its ability to balance depends on the total amount of electrolytes in the plasma and the concentration of colloidal proteins.

5) Supply of heat energy. Although the main function of proteins in the body is not to provide heat energy, the proteins in old or damaged tissue cells are constantly broken down to release energy.

Foods with a lot of protein include: livestock milk, such as cow's milk, goat's milk, mare's milk, etc.; Livestock meat, such as cattle, sheep, pigs, dogs, etc.; poultry meat, such as chickens, ducks, geese, quails, ostriches, etc.; Eggs, such as eggs, duck eggs, quail eggs, fish, shrimp, crabs, etc.; There are also soybeans, including soybeans, large green beans and black beans, among which soybeans have the highest nutritional value, and it is a high-quality protein in food**;

In addition, dried fruits such as sesame seeds, melon seeds, walnuts, almonds, pine nuts and other dried fruits have a higher protein content. Due to the different levels of amino acids in various foods, the types of amino acids they contain, and the content of other nutrients (fats, sugars, minerals, vitamins, etc.) is also different. All of the above foods are available, and high-protein foods can also be provided according to local specialties.

【Answer】c

Answer analysis] test question analysis: the compound with the most content in cells is water, a is wrong; Proteins with immune functions are antibodies, b error; The peptide chain forms a protein with a spatial structure in a certain way, c is correct; The basic units that make up proteins are amino acids, which all contain four elements: C, H, O, and N. Other elements may be different for different proteins, and D is wrong.

Test Center: This question tests the knowledge of protein structure and function. It is intended to test the ability to understand the main points of the knowledge learned and grasp the internal connections between knowledge.

The public examination life general knowledge questions, the correct rate is 39%, about protein, which of the following statements is wrong?

【Answer】d

Answer analysis] test question analysis: protein is a macromolecular organic matter, usually formed by the dehydration and condensation of 20 kinds of amino acids on the ribosome chain structure or circular structure, secreted proteins must be processed by the endoplasmic reticulum and Golgi apparatus to have normal function, neurotransmitters are small molecule organic substances, usually not proteins, transmit information between nerve cells, due to the selective expression of genes, the proteins contained in different cells of the organism are not exactly the same, so option d is correct.

【Answer】c

Analysis] The main components of chromosomes are DNA and proteins, a correct; The enzyme that acts as a catalyst does not change before and after the reaction, b is correct; A small amount of salt can promote the dissolution of protein, but if a concentrated salt solution is added to the protein solution, the solubility of the protein can be reduced and precipitated from the solution, this phenomenon is called salting out, according to the principle that the solubility of the protein in different concentrations of salt solution is different, and the spatial structure of the protein is not changed, c is incorrect; The protein molecule contains a peptide bond that can react with the biuret reagent in purple, d correctly.

Choose C. Table salt can cause proteins to precipitate (salting-out). However, as a rule, neutral salts cause the protein to be salted out without denaturation.

c.The protein precipitated by the action of table salt is denatured.

Answer C salt or precipitation is to add some inorganic salt solution to some protein solutions, which can reduce the solubility of the protein, so that the protein can be condensed and precipitated from the solution, this effect is called salting out, it is a physical change, recoverable, and does not change the structure of the protein, so answer C; Chromosomes are made up of proteins and DNA; The catalytic activity of the enzyme remains unchanged before and after the enzymatic reaction, so the molecular structure remains unchanged. The protein contains peptide bonds and the high biuret antistate group should produce a purple reaction.

Test site positioning: This question examines the properties of proteins. "

Answer: BA is one of the reasons for protein diversity, correct; Items c and d are statements about protein function, both correct; Due to the difference in the R group, there are about 20 kinds of amino acids that make up proteins, but not all proteins contain 20 kinds of amino acids, and they can be less than 20 kinds of amino acids.

Option A, the increase in the inner membrane area is not the reason for the high protein content of the inner membrane, but because there are many proteins that need to attach to the inner mitochondrial membrane for biochemical reactions.

Therefore, after long-term adaptation, many cristae are formed in the inner mitochondrial membrane to increase the area of the inner membrane.